Dynamic coupling analysis of the aerodynamic performance of a sedan passing by the bridge pylon in a crosswind

Abstract

In the crosswind environment, the flow field around a bridge pylon is complex and variable so that the vehicles are prone to side slip when passing by this region. In this situation, safety and comfort are severely affected. In this study, a dynamic coupling method that uses computational fluid dynamics (CFD) coupled with multibody dynamics was adopted to investigate the aerodynamic performance and dynamic response of a sedan passing by a bridge pylon in a crosswind. The overlapping grid technique was used to achieve the movement of the sedan in the CFD simulation. The mechanism of the interaction between the flow field around the sedan and the wake vortex around the bridge pylon was demonstrated. The influence of crosswind type on the aerodynamic performance and dynamic response was further studied. The results show that the flow field around the sedan could greatly influence the behavior of the sedan, mainly in terms of changes in lateral displacement and yaw angle. Additionally, the dynamic coupling method provides a more direct and realistic way to understand the interaction between the aerodynamic loads and the dynamic responses. Of the different wind types considered (sinusoidal, linear, step), the step crosswind produces the biggest average lateral force and yaw moment resulting in the largest lateral displacement and yaw angle.